1. Field of the Invention
The present invention relates to devices for driving a display panel such as a plasma display panel, and more particularly to a panel driving device capable of displaying correct video images which are in accord with address data.
2. Description of Related Art
As shown in FIG. 7, a driving device for a plasma display panel 21 is provided with: a shift register 115; an address driver section 118 having a latch circuit 116 and a driver 117; a Y sustain driver 119 that outputs Y sustain pulses; and an X sustain driver 120 that outputs X sustain pulses. The output terminals of the driver 117 of the address driver section 118, Y sustain driver 119, and X sustain driver 120 are coupled to predetermined electrodes of the panel 21, respectively.
As shown in FIG. 8, address data (i.e., data items a to z) for each line are sequentially loaded to the shift register 115 according to respective clock pulses. Also, upon rise of a clock pulse for loading the last data (data item z) for the line, a latch enable signal for activating the latch circuit 116 is risen, so that the address data (data items a to z ) for the line are latched and then supplied to the driver 117 simultaneously. Then, scan pulses are selectively applied to any one of the electrodes Y1 to Yn of the panel 21, and simultaneously therewith, data pulses DP1 to DPn corresponding to predetermined address data are applied to its column electrodes D1 to Dm, to illuminate certain cells (where wall charges are stored) and leave other cells nonilluminated (where no wall charges are stored). Successively, sustain pulses are applied through the Y sustain driver 119 and the X sustain driver 120, to selectively allow only the illuminating cells to repetitively emit light.
However, as shown in FIG. 9, when noise from large power circuitry within the device enters the latch enable signal through small signal circuitry, the noise causes the latch circuit 116 to latch erroneous data. For example, as shown in FIG. 9, a stream of address data erroneously starts with a data item c to have all the data items latched as shifted, hence producing noise spots in the picture displayed on the screen of the plasma display panel 21.